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Advisor(s)
Abstract(s)
Este projeto tem como primeiro objetivo a determinação do ângulo de atrito de base (Φ𝑏) para a estabilidade de uma superfície inclinada antes desta entrar em rotura e deslizamento recorrendo à metodologia de ensaio tilt test, através de um protótipo que desenvolvemos e posterior confirmação dos resultados num equipamento profissional cedido pela Universidade de Aveiro, aplicado a dois casos de estudo com propriedades díspares: o caso principal localizado na vertente natural de S. Simão (Gouveia, Amarante) e o caso secundário no talude rochoso de Santo Ovídio pertencente ao grupo de escutas 365 (Vila Nova de Gaia). Por forma a cumpri-lo, inicialmente, procedeu-se ao estudo geológico, geomorfológico, geotécnico e geomecânico através da técnica de amostragem linear in situ e à classificação e avaliação da estabilidade dos maciços recorrendo à aplicação de classificações geomecânicas (RMR, SMR, GSI) elaborando-se o respetivo zonamento geotécnico como trabalho de gabinete. Posteriormente procedeu-se à caracterização das amostras colhidas, que mais tarde foram serradas, para a realização do ensaio tilt test em dois provetes pré-dimensionados, num total de 128 combinações repetidas três vezes, obtendo o valor do ângulo de atrito β quando o provete superior desliza sobre o provete inferior e, através da mediana desses valores, o resultado Φ𝑏 pretendido. E como segundo objetivo, a determinação da resistência ao corte global e por zonas geotécnicas do maciço rochoso, centrando-se na execução de vários ensaios laboratoriais de forma a obter as variáveis necessárias (Φ𝑟 , JRC, JCS, 𝜎𝑛, α) a introduzir na expressão desenvolvida e aperfeiçoada de Barton & Choubey (1977) que permitam obter a informação necessária no sentido de antecipar deslizamentos ou queda de blocos em taludes naturais e prevenir acidentes em projetos futuros.
The main goal of this project is to determine the base friction angle (Φ𝑏) for the stability of an inclined surface before it breaks and slide using the tilt test methodology, through a prototype that we developed, and subsequent confirmation of the results in a professional equipment provided by the University of Aveiro, applied to two case studies with different properties: the main case located in the natural slope of S. Simão (Gouveia, Amarante) and the secondary case in the rock slope of Santo Ovídio where the scouts group 365 (Vila Nova de Gaia) have their facilities. In order to accomplish this goal, initially, a geological, geomorphologic, geotechnical and geomechanical study was carried out through the scanline sampling technique and the classification and evaluation of the rock masses stability using geomechanical classifications (RMR, SMR, GSI) by elaborating the respective geotechnical zoning as desk study. Later on, the samples collected were differentiated according to their characteristics, later saw-cut, to perform the tilt test in two pre-dimensioned samples, in a total of 128 combinations repeated three times, obtaining the friction angle value β when the upper sample slides over the lower sample and, through the median of these values, the intended result Φ𝑏. And as a second objective, the determination of the global shear strength and geotechnical zones of the rock mass, focusing on the execution of several laboratory tests in order to obtain the necessary variables (Φ𝑟 , JRC, JCS, 𝜎𝑛, α) to be inserted in the developed and improved expression of Barton and Choubey (1977) to provide the necessary information in way to anticipate landslides or rock falls on natural slopes and prevent accidents in future projects.
The main goal of this project is to determine the base friction angle (Φ𝑏) for the stability of an inclined surface before it breaks and slide using the tilt test methodology, through a prototype that we developed, and subsequent confirmation of the results in a professional equipment provided by the University of Aveiro, applied to two case studies with different properties: the main case located in the natural slope of S. Simão (Gouveia, Amarante) and the secondary case in the rock slope of Santo Ovídio where the scouts group 365 (Vila Nova de Gaia) have their facilities. In order to accomplish this goal, initially, a geological, geomorphologic, geotechnical and geomechanical study was carried out through the scanline sampling technique and the classification and evaluation of the rock masses stability using geomechanical classifications (RMR, SMR, GSI) by elaborating the respective geotechnical zoning as desk study. Later on, the samples collected were differentiated according to their characteristics, later saw-cut, to perform the tilt test in two pre-dimensioned samples, in a total of 128 combinations repeated three times, obtaining the friction angle value β when the upper sample slides over the lower sample and, through the median of these values, the intended result Φ𝑏. And as a second objective, the determination of the global shear strength and geotechnical zones of the rock mass, focusing on the execution of several laboratory tests in order to obtain the necessary variables (Φ𝑟 , JRC, JCS, 𝜎𝑛, α) to be inserted in the developed and improved expression of Barton and Choubey (1977) to provide the necessary information in way to anticipate landslides or rock falls on natural slopes and prevent accidents in future projects.
Description
Keywords
Maciços rochosos Superfícies rochosas Resistência ao corte Tilt test Ângulo de atrito Rock masses Rock surfaces Shear strength Friction angle